1. Field of the Invention
The present invention relates to a pneumatic tire in which a film made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending a thermoplastic resin with an elastomer is used as an inner liner layer. More particularly, the present invention relates to a pneumatic tire having an improved driving stability with reduced weight.
2. Description of the Related Art
Generally, a pneumatic tire has a casing structure including: a carcass layer bridged between a pair of bead portions; and a belt layer disposed on the outer circumferential side of the carcass layer. In addition, the pneumatic tire has an inner liner layer made of a butyl rubber formed along the inner surface of the carcass layer. In order to improve the driving stability of the pneumatic tire by increasing the casing stiffness thereof, it is effective to bury a reinforcing member including organic fiber cords or steel cords in a region from the bead portion to a side wall portion. However, the addition of the reinforcing member that is thickened due to the inclusion of such cords increases the weight of the tire.
On the other hand, a pneumatic tire is proposed in which a thermoplastic resin having an excellent air-permeation prevention ability is used in place of the butyl rubber as the material of an inner liner layer (see, for example, Japanese patent application Kokai publication No. Hei 8-217922). In this case, the thickness of the inner liner layer can be reduced, and thereby the reduction in the tire weight is achieved. However, even in such a pneumatic tire, when a reinforcing member is added to improve the driving stability by increasing the casing stiffness, the tire weight is accordingly increased, canceling out the tire weight reduction caused by the reduced thickness of the inner liner layer.